-LRB- CNN -RRB- -- The U.N. Security Council has condemned the killing of a French journalist who was reporting from the violence-racked Central African Republic .

French troops found the body of Camille Lepage during the search of a vigilante group 's vehicle in a western region of the country , French authorities said Tuesday .

`` All necessary means will be employed to shed light on the circumstances of this assassination and to find our compatriot 's murderers , '' the office of French President Francois Hollande said .

The U.N. Security Council said that `` those responsible for the killing shall be held accountable . ''

Widespread unrest

Sectarian violence has killed thousands of people and displaced many more in the Central African Republic since a coalition of mostly Muslim rebels deposed President Francois Bozize in March 2013 .

The rebels have since been forced from power , but Christian and Muslim militias have continued to clash despite the presence of French and African peacekeepers in the country .

Vigilante groups known as the anti-balaka , which translates to anti-machete , were formed to counter attacks on Christian communities by Seleka groups . But the anti-balaka have carried out deadly reprisals on Muslim communities .

Humanitarian groups have warned that the country risks descending into genocide .

Lepage 's body was found in an anti-balaka vehicle in the region of the western town of Bouar .

French Foreign Minister Laurent Fabius described Lepage as a `` journalist and photographer of great courage . ''

U.S. sanctions

News of her killing came on the same day that the White House announced that President Barack Obama had issued an executive order declaring an emergency in the Central African Republic and authorizing the use of sanctions to deal with the crisis .

The order also imposed sanctions on five individuals involved in the unrest .

The U.N. Security Council had in January unanimously voted to set up a sanctions regime against the people responsible for instability and atrocities in the country , putting three people on a sanctions committee list .

More than 2.5 million of the country 's roughly 5 million inhabitants are in need of humanitarian assistance and approximately one million people have been displaced , according to the White House .

`` Growing attacks perpetrated by both Muslim and Christian militias have brought CAR to a crisis of disastrous proportions , '' it said in a statement .

Mother shot on the road to safety , victim of CAR violence

Will the people of CAR ever get to return home ?

CNN 's Anna Maja Rappard and Laura Bernadini contributed to this report .

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French troops found Camille Lepage 's body in a vigilante group 's vehicle

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France vows to use `` all necessary means '' to find her killers

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Sectarian violence has killed thousands of people in CAR since last year

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The U.S. announces sanctions against some of those involved in the crisis